The article “Comparison of dual-kVp and dual-layer CT in simulations and real CT system measurements” by S. Kappler et al., IEEE Nuclear Science Symposium Conference Record (NSS/MIC), pages 4828 to 4831 (2008) discloses a dual-energy computed tomography system comprising a polychromatic x-ray source and a dual-layer detector. The computed tomography system is adapted to generate x-rays, which traverse an object to be imaged, while the x-ray source is rotated with respect to the object. The radiation, after having traversed the object, is detected by the dual-layer detector, wherein in a first layer, which is firstly hit by the radiation, a first scintillator generates first scintillation light depending on the detected radiation and wherein in a second layer, which is secondly hit by the radiation, a second scintillator generates second scintillation light depending on the radiation. The first scintillation light and the second scintillation light, which correspond to different energies of the detected radiation, are detected by photodiodes, wherein the photodiode for detecting the first scintillation light is arranged adjacent to a side surface of the first scintillator, i.e. not, for example, on a bottom surface of the first scintillator. This arrangement on the side surface leads to a technically relatively complex detector construction.